State concerned about increasing Lyme disease rates

Lindsey Parietti

Monday

Apr 28, 2008 at 12:01 AMApr 28, 2008 at 10:06 PM

A wet winter and warm weather are making it prime time for tick encounters as people begin to spend more time outdoors and the insects are actively looking for their first meal of the season, state health and environmental experts say.

A wet winter and warm weather are making it prime time for tick encounters as people begin to spend more time outdoors and the insects are actively looking for their first meal of the season, state health and environmental experts say.

"The wet spring and sudden warm weather has suddenly triggered a lot of tick activity," said Dr. Al DeMaria, director of communicable diseases at the state Department of Public health.

DeMaria said suburban development and the high number of deer in Middlesex and Worcester counties have contributed to a rising rate of Lyme disease, which is transmitted by the black-legged or deer tick.

In Middlesex County alone, the number of state-confirmed cases went from 257 in 2004 to 456 the next year, to 505 cases in 2006, the most recent year for which numbers are available.

DeMaria and other health experts predict those numbers aren't likely to decrease any time soon.

Although the state's deer population has been relatively stable over the past five years, Middlesex County and other suburban areas have a high density of deer, which, along with other mammals, serves as a host for ticks.

East of 1-495 where hunting is more restricted, there are about 25 deer per square mile, compared to Berkshires, which has reached the goal population of about 10 deer per square mile, said Dr. Rob Deblinger of the state Division of Fisheries and Wildlife.

DeMaria said the actual incidences of Lyme disease could be more than twice what are being recorded since each case has to be investigated by the state before it is declared Lyme disease, and often cases go unreported or the department does not have time to validate them.

Dr. Thomas Treadwell, director of the infectious disease clinic at MetroWest Medical Center in Framingham, said numbers can also be misleading since the test for Lyme disease yields a lot of false positives and false negatives.

"Last year definitely we saw a big increase in cases. We're going to try track it a little more carefully, so we know exactly what we're dealing with," he said.

"We tell our clinicians don't bother doing the test because if it's positive you're going to treat the patient and if it's negative you're going to treat the patient."

Even if patients have the disease, Treadwell advises them not to panic because 90 percent of patients do not get any symptoms beyond a rash and a fever.

"Younger patients actually have less complications than older patients, but complications are rare," he said of the neurological problems and arthritis that can be associated with the disease. "The only common complication is that some patients develop body aches and feel run down."

Pat Smith, president of the New Jersey-based Lyme Disease Association, said scientists are also starting to see global warming impact the spread of tick-related diseases.

"In Sweden, the ticks are almost as far north as the Arctic Circle and being seen in January, and we already now that the same thing is happening here," said Smith, who recently gave a talk at the New England Wildflower Society Framingham headquarters at Garden in the Woods.

"The disease used to be more of a disease that was in a lot of little pockets and now that's fanning out. People tend not to recognize this because there's not a lot of information out there," said Smith, who encourages community organizations to educate the public.

Climate change also brings new kinds of ticks to the area such as lone star ticks, which previously lived in New Jersey but are now found as far north as Maine, she said. Lone star ticks do not carry Lyme disease, but bites occasionally bring on circular rashes similar to early Lyme disease.

"I think global warming is probably playing a role, but even without (it), clearly the ticks that already exist in New England are the ones most important to transmitting Lyme disease," DeMaria said.

* Avoid areas where lawns or fields meet the forest, and areas where there are high grasses.

* Wear insect repellent and long pants when outside and check yourself, kids and pets for an insect the size of a poppy seed immediately after returning indoors. Ticks especially like warm, dark areas such as the groin, armpit, or behind the knee.